Sperm DNA integrity is of vital importance for foetal development
and birth of healthy offspring. Oxidative stress and consequent DNA
damage are the major cause of decline in semen quality in men with
varicocele. A preliminary study was conducted on 11 men with clinical
varicocele who also had high levels of reactive oxygen species (ROS), to
assess DNA damage in sperms and ROS levels before and after
varicocelectomy. Varicocelectomy resulted in rapid (1 month) significant
(P<0.001) decline in free radical levels and slow (3-6 months)
significant decline in DNA damage levels. Thus men undergoing
varicocelectomy should try concieving only 6 months following surgery.

Name: Indian Journal of Medical Research Publisher: Indian Council of Medical Research Audience: Academic Format: Magazine/Journal Subject: Biological sciences; Health Copyright: COPYRIGHT 2010 Indian Council of Medical
Research ISSN:0971-5916

Issue:

Date: Dec, 2010 Source Volume: 132 Source Issue: 6

Geographic:

Geographic Scope: India Geographic Code: 9INDI India

Accession Number:

247634565

Full Text:

Varicocele is one of the commonest surgically reversible causes of
infertility and affects about 40 per cent males with primary infertility
and 70-80 per cent males with secondary infertility. The pathophysiology
of varicocele induced infertility remains unknown. One of the mechanisms
by which it causes a decline in semen quality is increased testicular
temperature due to dilation and tortuosity of pampiniform plexus of
veins (1). In addition, a number of men with varicocele harbour genetic
abnormalities like Yq microdeletions (2). However, it is unknown whether
these are causally related or simply an incidental finding because of
the high prevalence of varicocele among infertile men.

Supraphysiological reactive oxygen species (ROS) levels have been
reported in men with varicocele and is one of the potential aetiological
factors in varicocele mediated deterioration in sperm concentration,
motility and morphology (3-5). Agarwal et al (6) reported that sperm
dysfunction is multifactorial in varicocele but oxidative stress is the
main cause. Oxidative stress can cause an alteration in the dynamics of
testicular microvascular blood flow, endocrine signaling and germ cell
apoptosis (7).

We conducted a preliminary study at the All India Institute of
Medical Sciences, New Delhi, from January 2009 to January 2010 on 11 men
(age 31.09 [+ or -] 2. (8) yr) with clinical varicocele (cytogenetically
normal, no Yq microdeletion, non smokers, non alcoholic, normal basal
metabolic index, no history of testicular or systemic infection), who
came for follow up for 3 and 6 months post-varicocelectomy. All men had
significantly high ROS levels in washed and neat semen (3,121,725.65 and
142,897.704 RLU per 20 million sperm/min respectively) as compared to
fertile age matched healthy controls (n=15) (800-1800 and 400-800 RLU
per 20 million sperm/min).

The fertile controls were men attending the clinic for vasectomy.
One month after varicocelectomy, there was a significant (P<0.001)
decline in ROS levels to 159,001.838 and 10,776.736 RLU per 20 million
sperm/min in washed and neat semen respectively. Three months
post-varicocelectomy the ROS levels further reduced to 98,971.081 and
6,456.249 RLU per 20 million sperm/min in washed and neat semen
respectively. ROS levels were measured by chemiluminiscence method using
luminol as probe (8). The study protocol was approved by the Institute
Ethics committee. The statistical comparison was done by Student's
t test.

DNA damage in sperms was assessed before and after varicocelectomy
(3 months) by comet assay (9) (single cell gel electrophoresis) in all
11 patients and showed no significant difference in DNA damage levels at
3 months post-varicocelectomy (despite significant decline in ROS
levels). Pre-varicocelectomy the mean DNA content in comet head was
39.18 [+ or -] 7.12 per cent which showed non-significant improvement to
41.21 [+ or -] 5.21 per cent one month after varicocelectomy and 44.02
[+ or -] 6.12 per cent three months post-varicocelectomy (quantity of
DNA in comet head is directly proportional to DNA integrity).

Six of the 11 men came for follow up after 6 months of
varicocelectomy. The ROS levels had declined further to 45,234.926 and
4,528.593 RLU per 20 million sperm/min in washed and neat semen
respectively. At this point, these patients showed a significant
improvement in the sperm DNA integrity and the mean DNA content in the
comet head increased to 67.42 [+ or -] 6.12 per cent, as compared to
44.02 [+ or -] 2.54 per cent at three months post-varicocelectomy.

Oxidative stress is a major cause of both nuclear and mitochondrial
DNA damage (8), and thus decline in ROS levels may also lead to decrease
in DNA damage. DNA integrity improved significantly only 6 months after
surgery. This may be because the spermatogenic cycle lasts for 64-72
days and at least one full cycle will need to be completed before the
beneficial effects are evident. This finding is of clinical significance
as men with varicocele may be counselled to try conceiving approximately
6 months post varicocelectomy.

Oxidative stress and oxidative stress induced DNA damage appear to
be major factors which adversely affect semen quality and lead to
infertility. Use of such sperm for ART may adversely affect
fertilization, embryogenesis and may have lifelong implications on
foetal health. Results of this pilot study highlight that infertile men
should be counselled to try conceiving only 6 months following
varicocelectomy. Varicocelectomy may be beneficial in reducing the ROS
levels, oxidative stress induced DNA damage with an overall improvement
of functional competence of sperm.